FIG. 1 schematically illustrates a conventional home lighting system 1. In a room 2, a lighting device 3 is mounted, for instance to the ceiling. The lighting device 3 comprises a fixed housing 4 and a replaceable light generating element 5, for instance an incandescent light bulb, which will hereinafter be indicated as “lamp”. A control switch 6 is mounted at a suitable location, for instance on the wall adjacent an entrance door. Electric wiring carrying mains voltage may be arranged in the ceiling. For connecting the lighting device 3, one mains wire may be connected to the lighting device directly. For being able to control the lighting device 3 with the control switch 6, at least one mains wire must be connected to the control switch 6 and one switch output wire is connected to the lighting device 3.
In this example, the lighting device 3 and the switch 6 are associated with each other, which means that the ON/OFF status of the lighting device 3, or perhaps even a dimming level, is controlled by the switch 6. Another example is an armature with an extension cord with a plug for connection with a wall socket, having a switch mounted in the extension cord.
In order to allow a user more flexibility and control comfort, systems have been developed where the lighting devices are controlled wirelessly by a remote control device. FIG. 2 schematically illustrates such system 10. The figure shows two lighting devices 13A, 13B, each connected to the electric mains wiring directly, each comprising a fixed housing 14A, 14B and a replaceable lamp 15A,15B, and each provided with a receiver 16A, 16B for receiving wireless control signals. The system 10 further comprises a remote control device 17, comprising a transmitter 18 for emitting wireless control signals, for instance, but exclusively, radio signals according to the Zigbee protocol. The remote control device 17 may be wall-mounted, but it may conveniently be a hand-held device, allowing the user to operate it from any location. The remote control device 17 may for instance have individual keys associated with individual receivers allowing individual switching of the associated lighting devices, or may have group keys to allow switching of a group of lighting devices simultaneously.
In each lighting device 13, there will be a controlling device (not shown for sake of simplicity) processing the received remote control signals and operating a built-in switch on the basis of these signals. This intelligence may physically be mounted in the housing 14, so that the lighting device 13 can be equipped with any standard lamp, but it is also possible that this intelligence is physically mounted in the lamp 15, so that it is simply possible to exchange lamps in an existing situation in order to obtain the wireless control facility; hereinafter, it will be assumed that the intelligence is mounted in the lamp, indeed. It is noted that in such situation there still would be the “hard” mains switch 6, which should be left in the position “ON”, but which can be turned to the position “OFF” in order to switch lamps off the hard way.
Building such lighting system 10 does not only require the physical mounting of the individual components. It also requires setting up a system definition, i.e. a relationship between the individual lamps and the remote control 17. For instance, the remote control 17 needs to know which lamps it is allowed to control, and the lamps need to know which remote control 17 they are to obey. If two neighbors have the same system, these systems should not interfere with each other. To this end, each device in the system has a device ID, and the command signals include the ID of the intended receiver lamp as well as the ID of the remote control 17 and a network ID. In an initiation process, a new lamp or a new remote control will be added to the network and lamp(s) and remote control(s) will be associated. The membership of network and association is protected, which means that a lamp will only obey commands given by the associated remote control 17.